realms-wiki/realms/lib/model.py
2014-11-17 11:25:26 -06:00

296 lines
11 KiB
Python

import json
from sqlalchemy import not_, and_
from datetime import datetime
from realms import db
class Model(db.Model):
"""Base SQLAlchemy Model for automatic serialization and
deserialization of columns and nested relationships.
Source: https://gist.github.com/alanhamlett/6604662
Usage::
>>> class User(Model):
>>> id = db.Column(db.Integer(), primary_key=True)
>>> email = db.Column(db.String(), index=True)
>>> name = db.Column(db.String())
>>> password = db.Column(db.String())
>>> posts = db.relationship('Post', backref='user', lazy='dynamic')
>>> ...
>>> default_fields = ['email', 'name']
>>> hidden_fields = ['password']
>>> readonly_fields = ['email', 'password']
>>>
>>> class Post(Model):
>>> id = db.Column(db.Integer(), primary_key=True)
>>> user_id = db.Column(db.String(), db.ForeignKey('user.id'), nullable=False)
>>> title = db.Column(db.String())
>>> ...
>>> default_fields = ['title']
>>> readonly_fields = ['user_id']
>>>
>>> model = User(email='john@localhost')
>>> db.session.add(model)
>>> db.session.commit()
>>>
>>> # update name and create a new post
>>> validated_input = {'name': 'John', 'posts': [{'title':'My First Post'}]}
>>> model.set_columns(**validated_input)
>>> db.session.commit()
>>>
>>> print(model.to_dict(show=['password', 'posts']))
>>> {u'email': u'john@localhost', u'posts': [{u'id': 1, u'title': u'My First Post'}], u'name': u'John', u'id': 1}
"""
__abstract__ = True
# Stores changes made to this model's attributes. Can be retrieved
# with model.changes
_changes = {}
def __init__(self, **kwargs):
kwargs['_force'] = True
self._set_columns(**kwargs)
def filter_by(self, **kwargs):
clauses = [key == value
for key, value in kwargs.items()]
return self.filter(and_(*clauses))
def _set_columns(self, **kwargs):
force = kwargs.get('_force')
readonly = []
if hasattr(self, 'readonly_fields'):
readonly = self.readonly_fields
if hasattr(self, 'hidden_fields'):
readonly += self.hidden_fields
readonly += [
'id',
'created',
'updated',
'modified',
'created_at',
'updated_at',
'modified_at',
]
changes = {}
columns = self.__table__.columns.keys()
relationships = self.__mapper__.relationships.keys()
for key in columns:
allowed = True if force or key not in readonly else False
exists = True if key in kwargs else False
if allowed and exists:
val = getattr(self, key)
if val != kwargs[key]:
changes[key] = {'old': val, 'new': kwargs[key]}
setattr(self, key, kwargs[key])
for rel in relationships:
allowed = True if force or rel not in readonly else False
exists = True if rel in kwargs else False
if allowed and exists:
is_list = self.__mapper__.relationships[rel].uselist
if is_list:
valid_ids = []
query = getattr(self, rel)
cls = self.__mapper__.relationships[rel].argument()
for item in kwargs[rel]:
if 'id' in item and query.filter_by(id=item['id']).limit(1).count() == 1:
obj = cls.query.filter_by(id=item['id']).first()
col_changes = obj.set_columns(**item)
if col_changes:
col_changes['id'] = str(item['id'])
if rel in changes:
changes[rel].append(col_changes)
else:
changes.update({rel: [col_changes]})
valid_ids.append(str(item['id']))
else:
col = cls()
col_changes = col.set_columns(**item)
query.append(col)
db.session.flush()
if col_changes:
col_changes['id'] = str(col.id)
if rel in changes:
changes[rel].append(col_changes)
else:
changes.update({rel: [col_changes]})
valid_ids.append(str(col.id))
# delete related rows that were not in kwargs[rel]
for item in query.filter(not_(cls.id.in_(valid_ids))).all():
col_changes = {
'id': str(item.id),
'deleted': True,
}
if rel in changes:
changes[rel].append(col_changes)
else:
changes.update({rel: [col_changes]})
db.session.delete(item)
else:
val = getattr(self, rel)
if self.__mapper__.relationships[rel].query_class is not None:
if val is not None:
col_changes = val.set_columns(**kwargs[rel])
if col_changes:
changes.update({rel: col_changes})
else:
if val != kwargs[rel]:
setattr(self, rel, kwargs[rel])
changes[rel] = {'old': val, 'new': kwargs[rel]}
return changes
def set_columns(self, **kwargs):
self._changes = self._set_columns(**kwargs)
if 'modified' in self.__table__.columns:
self.modified = datetime.utcnow()
if 'updated' in self.__table__.columns:
self.updated = datetime.utcnow()
if 'modified_at' in self.__table__.columns:
self.modified_at = datetime.utcnow()
if 'updated_at' in self.__table__.columns:
self.updated_at = datetime.utcnow()
return self._changes
def __repr__(self):
if 'id' in self.__table__.columns.keys():
return '%s(%s)' % (self.__class__.__name__, self.id)
data = {}
for key in self.__table__.columns.keys():
val = getattr(self, key)
if type(val) is datetime:
val = val.strftime('%Y-%m-%dT%H:%M:%SZ')
data[key] = val
return json.dumps(data, use_decimal=True)
@property
def changes(self):
return self._changes
def reset_changes(self):
self._changes = {}
def to_dict(self, show=None, hide=None, path=None, show_all=None):
""" Return a dictionary representation of this model.
"""
if not show:
show = []
if not hide:
hide = []
hidden = []
if hasattr(self, 'hidden_fields'):
hidden = self.hidden_fields
default = []
if hasattr(self, 'default_fields'):
default = self.default_fields
ret_data = {}
if not path:
path = self.__tablename__.lower()
def prepend_path(item):
item = item.lower()
if item.split('.', 1)[0] == path:
return item
if len(item) == 0:
return item
if item[0] != '.':
item = '.%s' % item
item = '%s%s' % (path, item)
return item
show[:] = [prepend_path(x) for x in show]
hide[:] = [prepend_path(x) for x in hide]
columns = self.__table__.columns.keys()
relationships = self.__mapper__.relationships.keys()
properties = dir(self)
for key in columns:
check = '%s.%s' % (path, key)
if check in hide or key in hidden:
continue
if show_all or key is 'id' or check in show or key in default:
ret_data[key] = getattr(self, key)
for key in relationships:
check = '%s.%s' % (path, key)
if check in hide or key in hidden:
continue
if show_all or check in show or key in default:
hide.append(check)
is_list = self.__mapper__.relationships[key].uselist
if is_list:
ret_data[key] = []
for item in getattr(self, key):
ret_data[key].append(item.to_dict(
show=show,
hide=hide,
path=('%s.%s' % (path, key.lower())),
show_all=show_all,
))
else:
if self.__mapper__.relationships[key].query_class is not None:
ret_data[key] = getattr(self, key).to_dict(
show=show,
hide=hide,
path=('%s.%s' % (path, key.lower())),
show_all=show_all,
)
else:
ret_data[key] = getattr(self, key)
for key in list(set(properties) - set(columns) - set(relationships)):
if key.startswith('_'):
continue
check = '%s.%s' % (path, key)
if check in hide or key in hidden:
continue
if show_all or check in show or key in default:
val = getattr(self, key)
try:
ret_data[key] = json.loads(json.dumps(val))
except:
pass
return ret_data
@classmethod
def insert_or_update(cls, cond, data):
obj = cls.query.filter_by(**cond).first()
if obj:
obj.set_columns(**data)
else:
data.update(cond)
obj = cls(**data)
db.session.add(obj)
db.session.commit()
def save(self):
if self not in db.session:
db.session.merge(self)
db.session.commit()
def delete(self):
if self not in db.session:
db.session.merge(self)
db.session.delete(self)
db.session.commit()
@classmethod
def query(cls):
return db.session.query(cls)
@classmethod
def get_by_id(cls, id_):
return cls.query().filter_by(id=id_).first()